Viral central nervous system (CNS) infections are a common cause of morbidity and mortality worldwide. Mammalian reoviruses, nonenveloped double-stranded RNA viruses, are a tractable experimental system for studies of neurotropic viral infections. Serotype 1 reoviruses spread hematogenously, infect ependymal cells, and cause hydrocephalus, whereas serotype 3 reoviruses spread through peripheral nerves, infect neurons, and cause lethal encephalitis. The a1 viral attachment protein mediates the distinctive patterns of spread and pathology in the murine CNS. However, mechanisms by which reovirus traverses axons and spreads from neuron-to-neuron are not known. While junctional adhesion molecule-A (JAM-A), the only known reovirus receptor, is required for efficient viral dissemination from the intestine, it is not required for viral growth or pathology in the CNS. These findings suggest that alternative neural-specific receptors govern reovirus CNS tropism. The central hypothesis of this work is that specific cellular determinants mediate neural spread of reovirus with infection of neurons requiring precise engagement of neural-specific receptors. Two integrated specific aims are proposed to test this hypothesis and advance knowledge of viral neuropathogenesis;in Specific Aim 1, molecular mechanisms by which reovirus is transmitted from neuron-to-neuron will be determined. Compartmentalized neuronal chambers will be utilized to define axonal requirements in neural spread, the involvement of molecular motors in transporting viral components within neurons, and the role of the synapse in neural transmission. In Specific Aim 2, neural-specific reovirus receptors will be identified using genomic, proteomic, and in silico approaches. Candidate receptors will be analyzed using models of reovirus neuronal infection and dissemination. This application integrates studies of reovirus neural transmission with functional analysis of cellular determinants of reovirus neurotropism to enhance an understanding of virus-induced CNS disease. PUBLIC HEALTH RELEVANCE: Studies described in this application will define mechanisms of reovirus CNS tropism and spread. This work will contribute new insights into general principles of viral neuropathogenesis and has the potential for discovery of novel neuronal regulatory pathways and CNS-specific viral receptors. Furthermore, the age restriction of reovirus disease presents a highly tractable model for studying specific determinants of pediatric CNS disease, which may reveal fundamental aspects of viral encephalitis in the young and identify unique targets for pediatric antiviral therapies.